TM 1-8415-215-12&P2-4.Operation of Standard Components.a. Fastening/Adjusting Chinstrap.(1) Fasten the chinstrap by inserting the strap through the D-rings, splitting the rings, and inserting the strap backthrough the inner D-ring.(2) To tighten the chinstrap, pull it through the inner D-ring to attain the desired fit (Figure 2-8).(3) To loosen the chinstrap, rotate the outer D-ring up and to the left by pulling on the two tabs of the outer D-ring.Pull the strap through the inner D-ring toward the left as needed to loosen or disengage the strap. If loosening, take upslack through D-rings by pulling the section of the strap under the chin to the right.NOTEFor most people, the chinstrap is long enough to allow for donning and doffingwithout repeated lacing through D-rings.Figure 2-8. Fastening Chinstrap2-5